Antifriction bearing



May9, 1961 INVENTORS I arren 6.

r 60. Pete EYQXW Q THEIR ATTORNEY a) I/ICZ'O United States PatentANTIFRICTION BEARING Warren G. Perin, Carmel, and Victor W. Peterson,Indianapolis, Ind., assignors to General Motors Corporation, Detroit,Mich., a corporation of Delaware riginal application Nov. 30, 1955, Ser.No. 550,015. Divided and this application Mar. 11, 1957, Ser. No.645,347

4 Claims. (Cl. 29-148.4)

This invention relates to antifriction bearings and particularly to animproved method of making a roller bearing wherein the rollingelementswill not slide or shift out of alignment under conditions ofsudden change in speed of bearing operation. I

This application is a division of our copending application, SerialNumber 550,015, filed November 30, 1955, now abandoned.

In the usual type of anti friction bearing for supporting radial loads,an inner race ring and an outer race ring are relatively rotatablethrough a. series of circumferentially disposed intervening rollingelements engaging race- Ways in these rings, the load being carried byusually less than half of these rolling elements in theload-carrying'zone of the bearing. In such a bearing embodyingcylindrical rollers, it is Well recognized that due to unevendistribution of stress concentrations, the roller ends are weaklysupported in comparison to the support of the intermediate portions ofthe rollers. As a result of this non-uniform stress distribution, it iscommon for these rollers to skew out of parallelism with the bearingaxis particularly when the rollers are running through the unloaded zoneof the bearing. Consequently, it is usual practice in a roller bearingto have a very loose fit of the rollers between the race rings whenpassing through the unloaded zone of the hearing. The axial misalignmentand improper rotation of such rollers in a hearing results in a scufiingaction on the roller surfaces and on the raceways with the result thatobjectionable internal friction is set up within the bearing and rapidwear is created causing bearing inaccuracies and short bearing life.Furthermore, when such roller bearings are operated under light load andunder conditions of sudden changes in rate of rotation, as occurs insome engines, it has been found that this scufiing and sliding of therollers is greatly increased causing damage to both rollers and racewayswhich results in very rapid bearing wear and sudden bearing failure.

It is, therefore, the object of this invention to provide an improvedmethod of making an antifriction roller hearing wherein the tendency ofthe rolling elements to slide and/ or become misaligned is substantiallyeliminated.

To these ends and also to improve generally upon devices and methodsofthis character, this invention con sists in the various mattershereinafter described and claimed. In its broader aspects, the inventionis not necessarily limited to the specific arrangement selected forillustrative purposes in the accompanying drawings where- In The singleillustration is a diagrammatic view showing our improved bearing inoperating position, certain features being greatly exaggerated to betterillustrate the invention.

In accordance with this invention, we have provided an antifrictionbearing having an inner race ring and an outer race ring 12 arranged forrelative antifrictional rotation through a series of circumferentiallydisposed rolling elements as rollers 14 for rolling engagement withPatented May 9, 1 961 annular raceways 16 and 18 respectively formed onthe inner and outer race rings. These rollers 14 preferably be includedin this invention. If desired, the rollers may be circumferentiallyspaced from each other by a suitable separator or cage between the racerings. The inner race ring 10, which has a bore 20 for receiving ashaft, has its raceway 16 precisely finished as a surface of revolutionherein illustrated as cylindrical and coaxial of the bore 20.

The outer race ring 12 is made initially to a circular form with anouter peripheral surface of revolution 22 coaxial with an outer raceway'18 against which the rollers fit in rolling engagement. With thisconstruction, the, outer race ring 12 has a uniform wall thicknessthroughout its circumference. V In the illustrated embodiment,.thesurfaces 18 and 22 are initially cylindrical but it is to be understoodthat these surfaces of revolution may be initially of other suitableannular forms. The inner and outer raceways 16 and 18 are ground to suchdiameters as to receive all of the rollers in light rolling engagementwith both raceways if the rollers were mounted in position while theouter race ring is in its initially circular form. How.- ever, beforeassembly of the bearing, the outer race ring 12 is sprung beyond itselastic limit to a slightly out of round condition wherein it maintainsa predetermined extent of ovality with a major axis A and a minor axisB. For clarity of illustration, this condition of ovality is greatlyexaggerated in the drawing since in some bearings.

V the actual difference in lengths of major and minor axes may be only afew thousandths of an inch or even a lesser distance. If necessary, theouter race ring;12 may be preheated and then sprung to the requiredfinal shape While still hot, care being taken that this outer race ringshall not be heated sufiiciently to detract from its re quired hardness.V t

' When the bearing is thereafter assembled with the rollers located incircumferential relation between the circular inner raceway 16 and theslightly oval outer raceway 18, a relative rotation of the race ringscauses the rollers 14 to freely roll under substantially no radialloadtas they pass through the diametrically disposed arcuate bearingzones centered about the opposite ends of the major axis A since theradial spacing of opposed raceway portions along the majoraxis slightlyexceeds the roller diameter. As these rollers approach and pass throughthe minor axis at diametrically opposite portions of the bearing, theywill roll through a slightly converging zone at one side of the minoraxis B and through a slightly diverging zone at the other side of thisaxis, the spacing of the opposite raceway portions being least along theminor axis. This raceway spacing along the minor axis is preferablyslightly less than a roller diameter. Hence, when the rollers arelocated in the short arcuate bearing zones through which the minor axiscentrally extends, these rollers will be under a radial load in apreloaded zone as indicated in the drawing. With this arrangement, the.rollers upon entering the slightly narrowing throats of the preloadedzones gradually increase their raceway contacts and slightly acceleratein their movements as they approach the minor axis B. This assures apositive and true rolling movement of the rollers as well as an aligningof these rollers into parallel relation with the bearing axis thuseliminating any tendency towards scuffing and roller misalignment as hasbeen common in prior types of roller bearings. Furthermore, ourarrangement of passing these rollers through preloaded zones isparticularly important in a bearing subjected. to sudden changes ofrotational speed under conditions of light load since this objectionalscuffing, sliding and misalignment has been eliminated 3 even under suchoperating conditions. It has been found that this roller scufiing andmisalignment in prior bearings subjected to sudden acceleration underlight load has been an important factor in greatly shortening bearinglife and in causing sudden bearing failure.

The assembled bearing is mounted in a suitable support such as a housing24 as by seating the outer race ring 12 in a cylindrical bore 25 in thishousing. We preferably employ a running fit of the outer race ring 12 inthis bore, this fit aiding in limiting the extent of ovality of theouter race ring. This mounting provides a slight clearance space 27between the wall of the bore 25 and the outer race ring 12 adjacent toeach preloaded zone of the bearing. The running fit of the outer racering 12 in the cylindrical bore 25 permits a turning of this race ringin the housing under conditions of sudden acceleration while the bearingcarries no appreciable load. When the bearing is operated under load,the outer race ring tends to remain stationary and may radially andresiliently yield slightly into the spaces 27 to avoid excessive loadingof the rollers within the preloaded zones. The illustration shows theload carrying zone disposed at each side of the minor axis B and withthe outer race ring portions adjacent the laterally disposed major axisA engaging the wall of the bore 25. With this arrangement, the slightyielding of the outer race ring at an end of the minor axis under workload will tend to distribute this load through more rollers in theloaded portion of the bearing thus improving the carrying capacity ofthe bearing while still assuring a free and true rolling movement of therollers in parallel relation to the bearing axis. It is not intended tolimit the operation of this hearing to the illustrated position since itperforms efiiciently irrespective of the angular relation of the majorand minor axes with reference to the load carrying zone indicated.

We claim:

1. The method of making an antifriction bearing having a series ofcircumferentially arranged rollers for rolling engagement between a pairof relatively rotatable race rings, comprising the steps of making acircular inner ring and a circular outer race ring, shaping each ring tohave a uniform radial wall section throughout its periphery, forming oneach ring a circular raceway coaxial with said ring, permanentlydeforming one of said rings by diametrically compressing said ringbeyond its elastic limit causing the ring to retain a predeterminedextent of ovality wherein its raceway will be correspondingly oval withpredetermined major and minor axes, inserting a series ofcircumferentially disposed rollers between the circular raceway and theraceway of predetermined ovality for rolling engagement along saidraceway throughout the entire circumferential extent of both raceways,and loosely positioning the deformed ring against a circular wall ofpredetermined diameter to control the extent of said ovality.

2. The method of making an antifriction bearing having a series ofrollers for rolling engagement between a pair of relatively rotatablecoaxial race rings, comprising the steps of making a circular inner racering having a uniform radial wall section, forming a cylindrical racewaythereon and coaxially therewith, making a hardened cylindrical outerrace ring having a uniform radial wall section, forming a cylindricalouter raceway on and coaxial with the outer race ring, heating the outerrace ring without impairing its hardness, diametrically deforming saidouter ring beyond its elastic limit to permanently shape it to aslightly oval contour having predetermined major and minor axes inperpendicular relation to each other, assembling between the circularraceway and the oval raceway a circumferentially disposed series ofcylindrical rollers for raceway rolling engagement throughout theperipheries of both raceways, the contour of the permanently oval outerraceway being such that the space between the raceways along the minoraxis is slightly less than that of a roller diameter and the spacingbetween the raceways along the major axis slightly exceeds that of aroller diameter, and mounting said outer ring for turning movementagainst a curved housing wall which limits the outer ring to apredetermined major diameter.

3. The method of providing a preloaded antifriction bearing having acircumferential series of rollers for rolling engagement between a pairof relatively rotatable race rings, comprising the steps of making acylindrical inner race ring having a uniform radial wall sectionthroughout its peripheral extent, forming a cylindrical raceway thereonand coaxial therewith, making a cylindrical outer race ring having auniform radial wall section throughout its peripheral extent, forming acylindrical raceway on and coaxial with the outer race ring, compressingthe outer race ring along a diameter of said ring to deform it beyondits elastic limit to a preset slightly oval contour and providing anoval outer raceway thereon having major and minor diameters inperpendicular relation to each other, assembling a series ofcircumferentially arranged rolling elements between the opposed racewaysand mounting the outer race ring for movement within a cylindricalhousing bore of a diameter slightly less than that of the major outerdiameter of the outer race ring to shape said outer race ring to apredetermined extent of ovality having predetermined major and minordiameters.

4. The method of making an antifriction bearing having a series ofrollers for rolling engagement between a pair of relatively rotatablerace rings, comprising the steps of making each race ring circular withuniform wall thickness, forming on each race ring a circular racewaycoaxial with its race ring, radially deforming one of the race ringsbeyond its elastic limit to permanently shape that ring and its racewayto a slightly oval contour, assembling a circumferentially disposedseries of rollers between the raceways, and mounting the oval race ringagainst a circular wall which limits said ring to a predetermined extentof ovality.

References Cited in the file of this patent UNITED STATES PATENTS1,803,966 Gibbons May 5, 1931 2,259,324 Robinson Oct. 14, 1941 2,633,627Olmstead Apr. 7, 1953 FOREIGN PATENTS 250,412 Great Britain Apr. 15,1926 125,542 Switzerland Apr. 16, 1928 837,249 France Nov. 3, 19381,079,848 France May 26, 1954

